a) Field of the Invention
The present invention relates to a socket which is turned off at a limiting temperature, and more particularly to a socket which is turned off if the working temperature is too high.
b) Description of the Prior Art
To prevent a circuit from issues of current overload, short circuit and overheating, a fuse or an overload protector is usually provided at the circuit. When the temperature of the circuit gets too high or the current gets too large, the fuse affected by the high temperature becomes blown or a bi-metal shrapnel of the overload protector becomes disengaged, so as to cause the circuit become open circuit and turned off to ensure electricity safety.
The Taiwan Utility Model Patent M509999, “Overheating Destructive Insulative Fixing Plate as well as a Plug and a Socket Using that Insulative Fixing Plate,” has disclosed an overheating destructive insulative fixing plate, which includes a connecting element and two limiting elements combined at two ends of the connecting element to form an H-shaped structure. The connecting element is put into the grooves formed on the conductive elements, enabling the two limiting elements to be abutted at an exterior side of the conductive element respectively and limiting the two conductive elements from contacting with each other. The connecting element is destructed when overheating, forming an open circuit between the two conductive elements.
However, each live wire spring plate and each live wire conductive plate will use an overheating destructive fixing plate, and each neutral wire spring plate and each neutral wire conductive plate will use another overheating destructive fixing plate, as shown in FIG. 21 of the abovementioned patent M509999. When a load (electric appliance) is connected between the live wire conductive plate and the neutral wire conductive plate, the electric current will flow through the live wire spring plate, the live wire conductive plate, the load (electric appliance), the neutral wire conductive plate and the neutral wire spring plate orderly to form an open path. If the location of overheating is between the neutral wire spring plate and the neutral wire conductive plate, then the fixing plate between the neutral wire spring plate and the neutral wire conductive plate will be destructed due to overheating. At this time, the fixing plate between the live wire spring plate and the live wire conductive plate may not be destructed. Therefore, the high electric current can still enter into the load prior to forming an open circuit; whereas, if electricity leaks out of the load and an operator touches the load under grounding, then the operator may get an electric shock.
Furthermore, in the embodiment shown in FIG. 1, FIG. 2 and FIG. 3 of the U.S. Pat. No. 9,257,798, a limiting element is used independently between the live wire conductive plate and the live wire contact portion, and another limiting element is also used independently between the neutral wire conductive plate and the neutral wire contact portion. Accordingly, that U.S. Pat. No. 9,257,798 is also provided with the same issue as the abovementioned Taiwan Utility Model Patent M509999. In other words, under overheating, in the structure disclosed in the U.S. Pat. No. 9,257,798, it is possible that only the limiting element between the neutral wire conductive plate and the neutral wire contact portion is destructed, but the limiting element between the live wire conductive plate and the live wire contact portion remains intact.